In general, a semiconductor manufacturing apparatus provided with a vacuum chamber serving as a processing room includes a pressure sensor installed on an outside of a wall of the chamber. The pressure sensor is connected to the vacuum chamber via a chamber pressure sensing port airtightly installed through the wall of the chamber in order to measure and manage a pressure or a vacuum level inside the chamber. In the prior art, a partition type shielding plate, which blocks contaminants, is provided in front of the chamber pressure sensing port so as to prevent the contaminants generated in the vacuum chamber from getting into and adhering to the pressure sensor through the chamber pressure sensing port.
However, when a semiconductor manufacturing apparatus for irradiating electron beams onto a substrate to be processed (a semiconductor wafer) in a vacuum chamber, e.g., an electron beam annealing equipment, outputs accelerated electrons of high energy into the chamber, X-rays are generated and scattered in the chamber to cause problems of being leaked out of the vacuum chamber through the chamber pressure sensing port.
It is generally known that a material with a narrow lattice spacing or a heavy material such as lead, stainless steel (SUS), lead-containing glass (containing 75% PbO) and the like can shield or attenuate the X-rays. However, even with the partition type shielding plate made of the material with a narrow lattice spacing, it is difficult to effectively shield a conventional pressure sensing port from the X-rays scattering in random directions. Further, the port opening area should be reduced in order to increase the degree of shielding or covering, thereby deteriorating a pressure sensing response characteristic.